Vehicular variable reflectance mirror reflective element

ABSTRACT

A vehicular variable reflectance mirror reflective element includes a rear glass substrate joined with a front glass sheet via a perimeter seal. An electrochromic medium disposed in an interpane cavity established between the rear glass substrate and the front glass sheet and bounded by the perimeter seal. With the rear glass substrate joined with the front glass sheet, the front glass sheet is cut at a front glass substrate portion to form a front glass substrate. A back plate is attached at the rear of the rear glass substrate. With the front glass sheet cut at the front glass substrate portions to form the front glass substrate having the rear glass substrate joined therewith via the perimeter seal, and with the back plate fixtured at a finishing tool, the cut edges of the front glass substrate are processed to provide a finished perimeter edge of the front glass substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 17/249,186, filed Feb. 23, 2021, now U.S. Pat. No. 11,433,814,which claims the filing benefits of U.S. provisional application Ser.No. 62/980,461, filed Feb. 24, 2020, which is hereby incorporated hereinby reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to the field of interiorrearview mirror assemblies for vehicles and more specifically to aprocess for manufacturing interior rearview mirror assemblies forvehicles.

BACKGROUND OF THE INVENTION

It is known to provide a mirror assembly that is adjustably mounted toan interior portion of a vehicle, such as via a ball pivot or jointmounting configuration, where the mirror casing and reflective elementare adjusted relative to the interior portion of a vehicle by pivotalmovement about the ball pivot configuration. The mirror casing andreflective element are pivotable about the ball pivot joint by a userthat is adjusting a rearward field of view of the reflective element.The mirror reflective element often comprises an electrochromicreflective element having a front glass substrate and a rear glasssubstrate with an electrochromic medium sandwiched between the front andrear glass substrates.

SUMMARY OF THE INVENTION

The present invention provides a process for forming an electro-opticmirror reflective element for a vehicular interior or exterior rearviewmirror assembly, with the front glass substrates of the mirrorreflective elements formed from a glass sheet that is not cut to formthe front glass substrates until after the rear glass substrates areadhered to the glass sheet. The back plate may also be attached at therear glass substrates before the front glass substrates are formed orcut from the glass sheet. The interpane cavities of the cells may befilled before or after the front glass substrates are formed or cut fromthe glass sheet. The cut edges of the formed or cut front glasssubstrates are thus finished (e.g., ground and/or polished) after thecells are formed. By attaching the back plates at the rear glasssubstrates before the front glass substrates are formed or cut from theglass sheet (and optionally before the rear glass substrates are matedwith the front glass sheet), the back plates can be used to fixture thesubstrates and sheet at the cutting tool and may be used to fixture themirror cells at the finishing tool, thereby providing enhanced accurateand secure fixturing of the cells during the cutting process and theedge finishing process.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a frameless interior rearview mirrorassembly formed via the process described herein;

FIG. 2 is a sectional view of a mirror reflective element having offsetglass substrates;

FIG. 3 is another sectional view of the mirror reflective element havingoffset glass substrates;

FIG. 4 is a sectional view of a mirror reflective element for aframeless rearview mirror assembly;

FIG. 5 is a sectional view of the mirror reflective element before thefront glass substrate has been formed from the glass sheet;

FIG. 6 is a perspective view of a glass sheet suitable for forming aplurality of front glass substrates;

FIG. 7 is a perspective view of the glass sheet of FIG. 6 ;

FIG. 8 is a perspective view of the glass sheet for forming a pluralityof front glass substrates, shown with a plurality of rear glasssubstrates adhered to the glass sheet, and with a plurality of mirrorback plates being attached at the rear of the rear glass substrates;

FIG. 9 is a side elevation view of the glass sheet with rear glasssubstrates and mirror back plates of FIG. 8 ;

FIG. 10 is a sectional view of a mirror assembly, where the finishedmirror cell is attached at a mirror casing;

FIG. 11 is a sectional view of another mirror reflective element, withthe front and rear substrates cut from sheets and with their perimeteredges finished together to form the desired rounded or curved peripheryof the mirror reflective element; and

FIG. 12 is an exploded perspective view showing a coated glass sheet forthe front shapes or substrates and a coated glass sheet for the rearshapes or substrates.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depictedtherein, an interior rearview mirror assembly 10 for a vehicle includesa casing 12 and a reflective element 14 positioned at a front portion ofthe casing 12 (FIG. 1 ). In the illustrated embodiment, mirror assembly10 is configured to be adjustably mounted to an interior portion of avehicle (such as to an interior or in-cabin surface of a vehiclewindshield or a headliner of a vehicle or the like) via a mountingstructure or mounting configuration or assembly 16. The mirrorreflective element comprises a variable reflectance mirror reflectiveelement that varies its reflectance responsive to electrical currentapplied to conductive coatings or layers at the glass substrates of thereflective element. Although shown as an interior rearview mirrorassembly, aspects of the process described below are also suitable foruse in manufacturing a mirror reflective element assembly for anexterior rearview mirror assembly. The glass sheets and/or substratesmay be formed as flat or planar sheets/substrates, or the front glasssheet may be curved or non-planar and the rear glass sheet or substratesmay be correspondingly curved to form curved or non-planar or non-unitmagnification exterior mirror reflective elements.

In the illustrated embodiment, and as shown in FIG. 2 , the mirrorreflective element 14 or mirror cell comprises a laminate constructionvariable reflectance electro-optic (such as electrochromic) reflectiveelement assembly having a front substrate 18 and a rear substrate 20with an electro-optic medium 22 (such as electrochromic medium)sandwiched therebetween and bounded by a perimeter seal 24. As shown inFIG. 2 , front substrate 18 has a front or first surface 18 a (thesurface that generally faces the driver of a vehicle when the mirrorassembly is normally mounted at the vehicle) and a rear or secondsurface 18 b opposite the front surface 18 a, and rear substrate 20 hasa front or third surface 20 a and a rear or fourth surface 20 b oppositethe front surface 20 a, with the electro-optic medium 22 disposedbetween the second surface 18 b and the third surface 20 a and boundedby the perimeter seal 24 of the reflective element. The second surface18 b has a transparent conductive coating 26 established thereat (suchas an indium tin oxide (ITO) layer, or a doped tin oxide layer or anyother transparent electrically semi-conductive layer or coating or thelike (such as indium cerium oxide (ICO), indium tungsten oxide (IWO), orindium oxide (IO) layers or the like or a zinc oxide layer or coating,or a zinc oxide coating or the like doped with aluminum or othermetallic materials, such as silver or gold or the like, or other oxidesdoped with a suitable metallic material or the like), while the thirdsurface 20 a has a metallic reflector coating 28 (or multiple layers orcoatings) established thereat. The front or third surface 20 a of rearsubstrate 20 may include one or more transparent semi-conductive layers(such as an ITO layer or the like), and one or more metallicelectrically conductive layers (such as a layer of silver, aluminum,chromium or the like or an alloy thereof), and may include multiplelayers. The mirror reflector coating 28 may comprise any suitablecoatings or layers, such as a transflective coating or layer, such asdescribed in U.S. Pat. Nos. 7,626,749; 7,274,501; 7,255,451; 7,195,381;7,184,190; 6,690,268; 5,140,455; 5,151,816; 6,178,034; 6,154,306;6,002,511; 5,567,360; 5,525,264; 5,610,756; 5,406,414; 5,253,109;5,076,673; 5,073,012; 5,115,346; 5,724,187; 5,668,663; 5,910,854;5,142,407 and/or 4,712,879, which are hereby incorporated herein byreference in their entireties, disposed at the front surface 20 a of therear substrate 20 (commonly referred to as the third surface of thereflective element) and opposing the electro-optic medium 22, such as anelectrochromic medium disposed between the front and rear substrates andbounded by the perimeter seal 24 (but optionally, the mirror reflectorcoating could be disposed at the rear surface 20 b of the rear substrate20 (commonly referred to as the fourth surface of the reflectiveelement), while remaining within the spirit and scope of the presentinvention).

The third surface 20 a defines the active EC area or surface of the rearsubstrate within the perimeter seal 24. The coated third surface 20 amay also be coated to define a tab-out region for providing electricalconnection of the conductive layers to an electrical clip of a connectoror bus-bar, such as the types described in U.S. Pat. Nos. 5,066,112 and6,449,082, which are hereby incorporated herein by reference in theirentireties.

Electro-optic (such as electrochromic) mirror reflective elements (foreither interior or exterior rearview mirrors) comprise glass substratesthat are produced from coated sheets or blanks of glass that aresubsequently turned into shapes or substrates or that are produced fromshapes or substrates that are subsequently (after the shapes are formed)coated with one or more layers of electrically conductive and/ormetallic reflector coatings. The coated shapes are then sequencedthrough numerous process steps to create a functioning EC mirrorreflective element.

Typically, the product is produced as a framed product that utilizes adouble offset design, with one glass substrate offset from the otherglass substrate to provide an offset region for electrically connectingthe electrically conductive coating of one of the glass substrates tothe anode (such as at the offset or overhang region 21 at the thirdsurface of the rear substrate) of the mirror cell, and another glasssubstrate offset region for electrically connecting the electricallyconductive coating of the other glass substrate to the cathode (such asat the offset or overhang region 19 at the second surface of the frontsubstrate) of the mirror cell (see FIGS. 2 and 3 ) to provide electricalcharge to the one or more electrically conductive layers at the glasssubstrates. The reflective element or cell is housed within a plasticbezel to conceal the offset and the perimeter seal.

With the advent of frameless mirrors (where the outer perimeter edgeportion of the front substrate is exposed and not “framed” by a plasticbezel), the offsets used for electrical connection to the cathode (atthe front substrate) are now different. For a typical frameless mirror(see the mirror cell 14 of FIG. 4 ), the rear glass substrate 20 issmaller (has smaller cross dimensions) than the front glass substrate18. Electrical connections for the anode and the cathode are providedeither via a wrapped conductor 30 at the rear substrate 20 or throughisolation of the conductor at the second surface 18 b and/or thirdsurface 20 a of the substrates. For example, and with reference to FIG.4 , the anode may electrically connect at a fourth surface portion of awrap-around conductor 30 that wraps around a perimeter edge portion ofthe rear substrate so as to electrically connect the fourth surfaceportion to the third surface electrically conductive metallic reflector,while the cathode may electrically connect at the second surfaceelectrically conductive transparent coating at the overhang region 31.

The geometries of the front and rear glass substrates of the framelessmirror reflective elements (with the front substrate being larger thanthe rear substrate and with no part of the rear substrate extendingbeyond any part of the front substrate) allow for the front glasssubstrate 18 or shape to be finalized after completion of the EC process(the process of creating a sealed cavity between the substrates andfilling the cavity with an electrochromic medium). Such a framelessmirror cell can now be manufactured out of a plate of glass after therest of the EC manufacturing process is complete, since the perimeter ofthe larger front glass shape can be cut out after the cell is formedwithout affecting the smaller rear glass shape. In the case of atraditional scoring cut machine, the front glass can be broken away atscore marks 32 because it is unobstructed by the rear glass substrate(as shown via the break-away arrows and the score marks 32 in FIG. 5 ).If a laser is used to cut the glass, the front substrate can be lasercut without concern of damaging the rear substrate and/or the coating atthe third surface of the rear substrate.

Because the rear glass substrates of frameless mirrors do not extendbeyond any part of the front glass substrates, and thus themanufacturing and/or glass cutting techniques applied to the front glasssubstrate do not interfere with the rear glass substrate, multiple glassmirror substrates may be made at one time in a plate type of approach ona sheet of glass that eventually forms the front glass substrates. Asshown in FIG. 6 , a glass sheet 118 or plate having the thicknessdesired for a front glass substrate, such as 2 mm or 2.5 mm (to allowfor a curved or rounded front perimeter edge having a radius ofcurvature of at least 2.5 mm to be formed after the front glass shapesare cut from the sheet) is coated at its rear surface 118 b, with maskedareas to create openings for EC glass.

Referring to FIGS. 6-9 , the plate is not cut until the entire or asignificant portion of the EC cell forming process is completed. Inother words, and such as shown in FIG. 6 , the front glass plate 118 iscoated at its rear surface 118 b (which will form the rear or secondsurface of the front glass substrate when the mirror cell is complete)and the rear glass substrates 20 are formed (cut from another glasssheet) and coated at their front or third surfaces 20 a. The cut andcoated rear glass substrates 20 are adhered to the already coated frontglass plate 118 (via the sealing material that forms the perimeter sealof the EC cell and that defines the interpane cavity between the glasssubstrates) at appropriate locations on the plate 118 corresponding towhat will become front glass substrates, with the perimeter seals 24adhering the respective rear substrates 20 to the plate 118 (see FIG. 8). The locations on the plate 118 corresponding to front glasssubstrates can be seen in FIGS. 6 and 7 via the placement of the coating26 at the rear surface 118 b of the plate 118 (however, to ease theassembly process, the entire rear surface of the plate may be coatedwith the transparent electrically conductive coating).

The interpane cavities of the respective cells (the cavities between thesecond surface 118 b of the glass sheet and the third surface of therespective rear substrates 20 that are bounded by the respectiveperimeter seals 24) can be filled with the electro-optic medium 22 andsealed before the glass plate 118 is cut to form the front glasssubstrates or shapes, such as by utilizing aspects of the processesdescribed in U.S. Pat. No. 7,255,451, which is hereby incorporatedherein by reference in its entirety. This provides a significantadvantage for manufacturing, allowing standardization of many differentshapes of mirrors that originate from a single plate design. Forexample, cutting multiple glass substrates from a single plate of glassallows a manufacturer to alter the designs cut from a single plate. Avariety of frameless mirror shapes can originate from the same glassplate or the same plate may be used to manufacture multiple mirrors ofthe same shape at the same time. This allows for flexibility in themanufacturing process to more readily adapt output to demand.

The process of the present invention reduces handling damage as well asreduces complexity in tooling and automation. The process improves theaccuracy of the part masking and allows for a single datum scheme to becarried through each process step to make the electrochromic mirrorcell. By using a consistent datum scheme, the variation due to locationcan be greatly minimized. The datum can originate in many ways, such asby using the edges of the plate, laser markings in either the raw orcoated glass or even with holes drilled in non-critical areas of theglass plate or other means as well to assure accurate and repeatablelocations during the EC cell forming process or operations. Datumschemes for the manufacturing processes of different embodiments orshapes or styles of frameless mirrors may differ to provide custom orspecific datum schemes for that particular frameless mirror. Optionally,datum schemes may be kept consistent between the manufacturing processesof different frameless mirrors to provide consistent reference pointsand operation of the tooling. In either situation, providing aconsistent datum scheme throughout multiple stages of manufacturing themirror cell at the plate or front glass substrate provides asignificantly more accurate and consistent reference point for thetooling operation.

Creating the mirror cells utilizing a glass plate 118 or blank allowsfor the part to be manufactured with minimal contact at the eventual“class A” surface (the exposed front surface 18 a and front perimeteredge 18 c regions of the front glass substrate 18). This directlyinfluences the quality and yield of the manufacturing process in apositive manner. The final “class A” edge and surface can be created asthe last or nearly the last step in the EC cell forming/assemblingprocess. Thus, the manufacturing process will provide feweropportunities for the “class A” surface or edge to be scratched,scuffed, cracked, chipped, or otherwise damaged.

Optionally, given that manufacturing multiple frameless mirrorsutilizing a singular plate provides much improved position accuracy, theattachment feature 34 for the mirror cell 14 to the housing 12(typically referred to as the back plates) can be attached to the rearsubstrates 20 before the mirror shape is cut from the plate 118 (seeFIGS. 8 and 9 ). By affixing or adhering the back plate 34 to the mirrorcells before the front substrate is cut from the glass plate 118, theassembly costs can be reduced. Also, the back plate 34 will be preciselylocated and aligned relative to the cut edge of the glass, which isbeneficial in assuring that the final product assembles to the mirrorcasing 12 with minimal misalignment between the glass and the mirrorcasing (see FIG. 10 ). The fit of the rear glass substrate to thehousing may also be improved by such a process.

Additionally, for frameless mirrors, the front glass shapes orsubstrates 18 cut from the plate may require post-cut treatment of theedges (such as grinding and polishing the perimeter edge to provide therounded periphery). The back plate 34 can be designed to serve as alocating and clamping feature, which will allow the grinding andpolishing operations to be more readily automated, with the mirror cell(and front substrate that is to be ground/polished) being precisely heldin its location during the grinding and polishing operations. This is animprovement over the grinding and polishing of individual shapes orsubstrates, which are held via a vacuum attachment or a mechanical clampdirectly attached to the glass substrate, which can allow a part to slipor move slightly during the grinding/polishing, resulting in damage ordefect and ultimately having to scrap the substrates. By firstpermanently attaching the back plate or attachment plate 34 at the rearsurface 20 b of the rear substrate 20 (such as via adhesive ordouble-sided tape or the like), such that the formed cell has the backplate affixed thereto before the grinding/polishing processes (andbefore the front glass substrate is even cut or broken from the largerglass sheet), the back plate can be securely held at a fixture of thefinishing tool to substantially preclude or prevent any movement of thefront glass substrate during the grinding/polishing processes. Such afeature thus can allow for higher machining (grinding and polishing)speeds as such an arrangement can withstand higher loads and forcesapplied to the glass substrate without causing movement of the substratethat is being ground/polished. This approach increases the precision ofthe location of the finished edge of the glass substrate and uses theattachment feature used to assemble the mirror to the housing to fixtureand hold the mirror cell and front glass substrate securely in placeduring the finishing processes.

Optionally, the above described processes may also be suitable for bentglass shapes (such as for exterior rearview mirror assemblies), where abent glass blank or sheet is utilized throughout the EC cell formingprocess and the final glass shape is created as the final process (bycutting the front glass blank to the desired front glass shapes at theend of the process).

The assembly process is also suitable for use in manufacturing mirrorcells 14′ (FIG. 11 ) where electrical connections of the anode andcathode to the respective electrically conductive coatings at therespective surfaces of the glass substrates are made through the rearglass substrate 20′ (such as by vias or passageways 36 formed throughthe rear glass substrate 20′). With such a design, the front and rearsubstrates 18′, 20′ may be formed with the same profile, and optionallymay both be ground and polished (via a common process that grinds and/orpolishes both substrates together) to provide a curved or roundedperiphery around the mirror cell. Thus, the curvature of the cut edge 18c′ of the front glass substrate 18′ aligns with or coincides with orcorresponds to the curvature of the cut edge 20 c′ of the rear glasssubstrate 20′ to achieve a common profile. In such an application, themirror substrates can be thinner (i.e., the front glass sheet need notbe 2 mm or 2.5 mm thick since the rounded perimeter edge is formed byboth the front and rear substrates) and can be cut and machined together(because the rear substrate has the same profile or radius of curvatureof the rounded perimeter edge as that of the front substrate) to createthe surface edge that appears to be a single piece of glass, but isactually made from two pieces of glass laminated together. This mirrorcell construction may be thinner and lighter than other configurations.

Referring to FIG. 12 , when the front and rear substrates share a commonprofile, both the front and rear glass can be formed from glass plates.This allows for greater gains in the manufacturing processes. The mirrorshapes can be extracted or formed from the dual plate process at or nearthe end of the cell forming process, further increasing the precisionand reducing the handling damage to the “class A” surface of the finalmirror cell.

Thus, the manufacturing steps of the process described herein arefollowed substantially, but instead of placing rear glass substrates atthe front glass plate 118, a rear glass plate 120, from which multiplerear glass substrates will be extracted, is disposed at and adhered orbonded to via a plurality of perimeter seals disposed at one of theopposing surfaces of the glass plates or sheets. As shown in FIG. 12 ,both the front plate 118 and the rear plate 120 may be coated (such aswith a transparent conductive coating 26 at the rear surface 118 b ofthe front plate 118 and a metallic reflector coating 28 at the frontsurface 120 a of the rear plate 120) and then adhered to one another viathe perimeter seals. For illustrative purposes, FIG. 12 depicts thecoated surfaces of the front and rear plates as both facing upwards, butit should be understood that when joined, the coated surfaces face oneanother (such as in FIGS. 2 and 3 ).

After the perimeter seal is applied (to either of the opposing surfacesand around the respective interpane cavity to be formed) to adhere thefront glass plate to the rear glass plate, additional manufacturingsteps may take place (such as curing the perimeter seal material,filling the interpane cavity with the electro-optic medium, plugging thefill hole through the perimeter seal, and/or affixing the back plate atthe rear glass plate via curing or bonding the perimeter seal at theplates) before the individual mirror cells are cut from the glassplates. After the mirror cells are cut from the front and rear glassplates, the perimeter edges of both the front and rear glass are groundand polished together to produce a curved or rounded periphery edgearound the cell. Thus, the process where both the front glass substrateand the rear glass substrate originate from glass plates after theplates are joined or mated together via the perimeter seals provides amethod for producing mirror cells (such as those in FIG. 11 ) where thefront and glass substrate are formed with the same profile, share aperipheral edge, and thus appear to be formed from a single piece ofglass and can also be made thinner and lighter than other mirrorassemblies. Optionally, the process may also be suitable for mirrorcells that have front and rear substrates with non-matching perimeteredges.

Therefore, the present invention provides a process of forming anelectrochromic mirror cell using a glass sheet for the front glasssubstrate during the forming process, with the step of cutting orforming the front glass shape being one of the last steps in theprocess, after the cell is formed and filled. The process comprisesstarting with a sheet of glass (such as, for example, a glass sheethaving a thickness dimension of at least 2 mm, such as 2.5 mm orthereabouts) and coating the sheet of glass and positioning multiplerear glass substrates (already cut or formed) at the coated surface andadhering the rear glass substrates to the sheet via the respectiveperimeter seals of the respective cells. The mirror shapes or frontsubstrates are then cut from the sheet, resulting in individual mirrorcells. The cells may be filled while part of the sheet, or may be filledlater, after the front substrates are cut from the sheet. After thefront substrates or shapes are cut from the sheet, the perimeter edge ofthe front substrates are ground and/or polished to provide the finishedperimeter edge (such as a rounded edge having a radius of curvature ofat least 2.5 mm). Optionally, the back plates may be attached at therear substrates (attached at the front glass sheet) prior to cutting thefront glass substrates from the front glass sheet, or the back platesmay be attached at the rear substrates after cutting the front glasssubstrates from the front glass sheet but before the grinding andpolishing steps that finish the perimeter edge and surface of the frontglass substrate. Optionally, the back plates may be attached at the rearglass substrates (or at the rear glass sheet) before the rear glasssheet or substrates are attached at the front glass sheet (such that theback plate may be used to position the rear glass substrate or sheet atthe appropriate location relative to the front glass sheet). Optionally,the front glass sheet may be thinner and the rear glass substrate andfront glass substrate, when combined and after being cut from the glasssheet, may be machined or processed together to provide the roundedperimeter edge of the mirror reflective element.

Optionally, the rear glass substrates may be applied to the front glasssheet or plate as a rear glass sheet or plate, where both front and rearshapes may be extracted from the plates near the end of themanufacturing process (e.g., after filling the interpane cavities withthe electrochromic medium). Thus, when the rear glass substratescomprise a rear glass sheet, at least the rear glass substrate regionsare coated and the rear glass sheet is adhered at the coated surface ofthe front glass substrate via a plurality of perimeter seals. The mirrorcells are filled with the electro-optic medium and the mirror shapes arecut from the front and rear glass sheets. The perimeter edge of thefront and rear glass substrates are ground and polished together toprovide a finished perimeter edge. The back plates are attached at therear substrates either before or after cutting the shapes from thesheets and either before or after grinding and polishing the perimeteredges of the cut glass substrates. Attaching the back plates prior tocutting the shapes and/or grinding and polishing the perimeter edgeallows the back plate to be used as a clamping point in the grinding andpolishing and finishing process or processes.

The mirror assembly may comprise any suitable construction, such as, forexample, a mirror assembly with the reflective element being nested inthe mirror casing and with a bezel portion that circumscribes aperimeter region of the front surface of the reflective element, or withthe mirror casing having a curved or beveled perimeter edge around thereflective element and with no overlap onto the front surface of thereflective element (such as by utilizing aspects of the mirrorassemblies described in U.S. Pat. Nos. 7,184,190; 7,274,501; 7,255,451;7,289,037; 7,360,932; 7,626,749; 8,049,640; 8,277,059 and/or 8,529,108,which are hereby incorporated herein by reference in their entireties)or such as a mirror assembly having a rear substrate of an electro-opticor electrochromic reflective element nested in the mirror casing, andwith the front substrate having curved or beveled perimeter edges, orsuch as a mirror assembly having a prismatic reflective element that isdisposed at an outer perimeter edge of the mirror casing and with theprismatic substrate having curved or beveled perimeter edges, such asdescribed in U.S. Pat. Nos. 8,508,831; 8,730,553; 9,598,016 and/or9,346,403, and/or U.S. Publication Nos. US-2014-0313563 and/orUS-2015-0097955, and/or U.S. Des. Pat. Nos. D633,423; D633,019; D638,761and/or D647,017, which are hereby incorporated herein by reference intheir entireties (and with electrochromic and prismatic mirrors of suchconstruction are commercially available from the assignee of thisapplication under the trade name INFINITY™ mirror).

Optionally, the reflective element may include an opaque orsubstantially opaque or hiding perimeter layer or coating or banddisposed around a perimeter edge region of the front glass substrate(such as at a perimeter region of the rear or second surface of thefront glass substrate) to conceal or hide or the perimeter seal fromviewing by the driver of the vehicle when the mirror assembly isnormally mounted in the vehicle. Such a hiding layer or perimeter bandmay be reflective or not reflective and may utilize aspects of theperimeter bands and mirror assemblies described in U.S. Pat. Nos.5,066,112; 7,626,749; 7,274,501; 7,184,190; 7,255,451; 8,508,831 and/or8,730,553, which are all hereby incorporated herein by reference intheir entireties. The hiding layer is applied at the surface of theglass sheet before the rear glass substrates (or rear glass sheet) areattached at the front glass sheet during the EC cell forming process.

The back plate may comprise any suitable construction (such as formedvia injection molding a plastic or polymeric resin or material).Optionally, for example, a common or universal back plate, whereby theappropriate or selected socket element or pivot element (such as asocket element or such as a ball element or the like) is attached to theback plate to provide the desired pivot joint for the particular mirrorhead in which the back plate is incorporated. Optionally, when moldingthe back plate (such as via injection molding the plastic or polymericresin or material), a different insert may be provided to integrallymold a portion of or all of a ball member or the like (such as a portionof a base of a ball member, whereby the ball member may comprise ametallic ball member that is insert molded at the base and at the rearof the back plate during the injection molding process that forms theback plate, such as by utilizing aspects of the mirror assembliesdescribed in U.S. Pat. Nos. 7,855,755; 7,249,860 and 6,329,925 and/orU.S. Pat. Pub. No. US-2006-0061008, which are hereby incorporated hereinby reference in their entireties).

Changes and modifications in the specifically described embodiments maybe carried out without departing from the principles of the presentinvention, which is intended to be limited only by the scope of theappended claims as interpreted according to the principles of patentlaw.

1. A vehicular variable reflectance mirror reflective element, thevehicular variable reflectance mirror reflective element comprising: avehicle mirror-shaped rear glass substrate; wherein the rear glasssubstrate is joined with a front glass substrate portion of a frontglass sheet via a perimeter seal; wherein the front glass sheet has afirst surface and a second surface separated by a thickness of the frontglass sheet, and wherein a transparent electrically conductive layer isdisposed at the second surface of the front glass sheet at least at thefront glass substrate portion; wherein the rear glass substrate has athird surface and a fourth surface separated by a thickness of the rearglass substrate, and wherein a mirror reflector is disposed at the thirdsurface of the rear glass substrate; wherein the perimeter sealestablishes an interpane cavity between the third surface of the rearglass substrate and the second surface of the front glass substrateportion of the front glass sheet; an electrochromic medium disposed inthe interpane cavity with the rear glass substrate joined with the frontglass sheet and with the interpane cavity established between the thirdsurface of the rear glass substrate and the second surface of the frontglass sheet and bounded by the perimeter seal; wherein, with the rearglass substrate joined with the front glass sheet, the front glass sheetis cut at the front glass substrate portion to form a vehiclemirror-shaped front glass substrate having the rear glass substratejoined therewith via the perimeter seal; a back plate attached at therear of the rear glass substrate; and wherein, with the front glasssheet cut at the front glass substrate portion to form the front glasssubstrate having the rear glass substrate joined therewith via theperimeter seal, and with the back plate fixtured at a finishing tool,the cut edges of the front glass substrate are processed to provide afinished perimeter edge of the front glass substrate.
 2. The vehicularvariable reflectance mirror reflective element of claim 1, wherein theback plate is attached at the rear of the rear glass substrate after therear glass substrate is joined with the front glass sheet.
 3. Thevehicular variable reflectance mirror reflective element of claim 2,wherein the back plate is attached at the rear of the rear glasssubstrate before the front glass sheet is cut at the front glasssubstrate portion to form the front glass substrate.
 4. The vehicularvariable reflectance mirror reflective element of claim 1, wherein theback plate is attached at the rear of the rear glass substrate beforethe rear glass substrate is joined with the front glass sheet.
 5. Thevehicular variable reflectance mirror reflective element of claim 1,wherein, with the rear glass substrate joined with the front glasssheet, no part of the rear glass substrate extends beyond a perimeter ofthe front glass substrate portion of the front glass sheet.
 6. Thevehicular variable reflectance mirror reflective element of claim 1,wherein the front glass sheet has a thickness dimension of at least 2mm.
 7. The vehicular variable reflectance mirror reflective element ofclaim 6, wherein the processed cut edges of the front glass substrateprovides a finished rounded perimeter edge having a radius of curvatureof at least 2.5 mm.
 8. The vehicular variable reflectance mirrorreflective element of claim 1, wherein the electrochromic medium isdisposed in the interpane cavity after the front glass sheet is cut atthe front glass substrate portion to form the front glass substrate. 9.The vehicular variable reflectance mirror reflective element of claim 1,wherein the electrochromic medium is disposed in the interpane cavitybefore the front glass sheet is cut at the front glass substrate portionto form the front glass substrate.
 10. The vehicular variablereflectance mirror reflective element of claim 1, wherein the finishingtool comprises a grinding and/or polishing tool that grinds and/orpolishes the cut edges of at least the front glass substrate.
 11. Thevehicular variable reflectance mirror reflective element of claim 1,wherein the finishing tool comprises a grinding and/or polishing toolthat grinds and/or polishes the cut edges of the front glass substrateand the rear glass substrate during a common grinding and/or polishingoperation.
 12. The vehicular variable reflectance mirror reflectiveelement of claim 1, comprising a hiding layer disposed at the secondsurface of the front glass sheet at a perimeter region of the frontglass substrate portion, wherein the hiding layer comprises anelectrically conductive reflective hiding layer, and wherein, with therear glass substrate joined with the front glass sheet, the hiding layerconceals the perimeter seal from view through the front glass sheet. 13.The vehicular variable reflectance mirror reflective element of claim 1,wherein the rear glass substrate is part of a rear glass sheet, andwherein the rear glass sheet is cut at a rear glass substrate portion toform the rear glass substrate.
 14. The vehicular variable reflectancemirror reflective element of claim 1, wherein the back plate isadhesively attached at the rear of the rear glass substrate.
 15. Thevehicular variable reflectance mirror reflective element of claim 14,wherein the back plate is adhesively attached at the rear of the rearglass substrate via double-sided tape.
 16. A vehicular variablereflectance mirror reflective element, the vehicular variablereflectance mirror reflective element comprising: a vehiclemirror-shaped rear glass substrate; wherein the rear glass substrate isjoined with a front glass substrate portion of a front glass sheet via aperimeter seal; wherein the front glass sheet has a first surface and asecond surface separated by a thickness of the front glass sheet, andwherein a transparent electrically conductive layer is disposed at thesecond surface of the front glass sheet at least at the front glasssubstrate portion; wherein the rear glass substrate has a third surfaceand a fourth surface separated by a thickness of the rear glasssubstrate, and wherein a mirror reflector is disposed at the thirdsurface of the rear glass substrate; wherein the perimeter sealestablishes an interpane cavity between the third surface of the rearglass substrate and the second surface of the front glass substrateportion of the front glass sheet; an electrochromic medium disposed inthe interpane cavity with the rear glass substrate joined with the frontglass sheet and with the interpane cavity established between the thirdsurface of the rear glass substrate and the second surface of the frontglass sheet and bounded by the perimeter seal; wherein, with the rearglass substrate joined with the front glass sheet, the front glass sheetis cut at the front glass substrate portion to form a vehiclemirror-shaped front glass substrate having the rear glass substratejoined therewith via the perimeter seal; a back plate attached at therear of the rear glass substrate; wherein, with the front glass sheetcut at the front glass substrate portion to form the front glasssubstrate having the rear glass substrate joined therewith via theperimeter seal, and with the back plate fixtured at a finishing tool,the cut edges of the front glass substrate are processed to provide afinished perimeter edge of the front glass substrate; wherein thefinishing tool comprises a grinding and/or polishing tool that grindsand/or polishes the cut edges of at least the front glass substrate; andwherein, with the rear glass substrate joined with the front glasssheet, and with the front glass substrate formed by cutting the frontglass sheet, no part of the rear glass substrate extends beyond aperimeter of the front glass substrate.
 17. The vehicular variablereflectance mirror reflective element of claim 16, wherein the backplate is attached at the rear of the rear glass substrate after the rearglass substrate is joined with the front glass sheet.
 18. The vehicularvariable reflectance mirror reflective element of claim 17, wherein theback plate is attached at the rear of the rear glass substrate beforethe front glass sheet is cut at the front glass substrate portion toform the front glass substrate.
 19. The vehicular variable reflectancemirror reflective element of claim 16, wherein the back plate isattached at the rear of the rear glass substrate before the rear glasssubstrate is joined with the front glass sheet.
 20. The vehicularvariable reflectance mirror reflective element of claim 16, wherein thefront glass sheet has a thickness dimension of at least 2 mm.
 21. Thevehicular variable reflectance mirror reflective element of claim 20,wherein the processed cut edges of the front glass substrate provides afinished rounded perimeter edge having a radius of curvature of at least2.5 mm.
 22. The vehicular variable reflectance mirror reflective elementof claim 16, wherein the finishing tool comprises a grinding and/orpolishing tool that grinds and/or polishes the cut edges of the frontglass substrate and the rear glass substrate during a common grindingand/or polishing operation.
 23. The vehicular variable reflectancemirror reflective element of claim 16, wherein the back plate isadhesively attached at the rear of the rear glass substrate.
 24. Thevehicular variable reflectance mirror reflective element of claim 23,wherein the back plate is adhesively attached at the rear of the rearglass substrate via double-sided tape.
 25. A vehicular variablereflectance mirror reflective element, the vehicular variablereflectance mirror reflective element comprising: a vehiclemirror-shaped rear glass substrate; wherein the rear glass substrate isjoined with a front glass substrate portion of a front glass sheet via aperimeter seal; wherein the front glass sheet has a first surface and asecond surface separated by a thickness of the front glass sheet, andwherein a transparent electrically conductive layer is disposed at thesecond surface of the front glass sheet at least at the front glasssubstrate portion; wherein the rear glass substrate has a third surfaceand a fourth surface separated by a thickness of the rear glasssubstrate, and wherein a mirror reflector is disposed at the thirdsurface of the rear glass substrate; wherein the perimeter sealestablishes an interpane cavity between the third surface of the rearglass substrate and the second surface of the front glass substrateportion of the front glass sheet; wherein, with the rear glass substratejoined with the front glass sheet, no part of the rear glass substrateextends beyond a perimeter of the front glass substrate portion of thefront glass sheet; an electrochromic medium disposed in the interpanecavity with the rear glass substrate joined with the front glass sheetand with the interpane cavity established between the third surface ofthe rear glass substrate and the second surface of the front glass sheetand bounded by the perimeter seal; wherein, with the rear glasssubstrate joined with the front glass sheet, the front glass sheet iscut at the front glass substrate portion to form a vehicle mirror-shapedfront glass substrate having the rear glass substrate joined therewithvia the perimeter seal; a back plate adhesively attached at the rear ofthe rear glass substrate; and wherein, with the front glass sheet cut atthe front glass substrate portion to form the front glass substratehaving the rear glass substrate joined therewith via the perimeter seal,and with the back plate fixtured at a finishing tool, the cut edges ofthe front glass substrate are processed to provide a finished perimeteredge of the front glass substrate.
 26. The vehicular variablereflectance mirror reflective element of claim 25, wherein the backplate is attached at the rear of the rear glass substrate before thefront glass sheet is cut at the front glass substrate portion to formthe front glass substrate.
 27. The vehicular variable reflectance mirrorreflective element of claim 25, wherein the back plate is attached atthe rear of the rear glass substrate after the rear glass substrate isjoined with the front glass sheet.
 28. The vehicular variablereflectance mirror reflective element of claim 25, wherein theelectrochromic medium is disposed in the interpane cavity after thefront glass sheet is cut at the front glass substrate portion to formthe front glass substrate.
 29. The vehicular variable reflectance mirrorreflective element of claim 25, wherein the electrochromic medium isdisposed in the interpane cavity before the front glass sheet is cut atthe front glass substrate portion to form the front glass substrate. 30.The vehicular variable reflectance mirror reflective element of claim25, wherein the finishing tool comprises a grinding and/or polishingtool that grinds and/or polishes the cut edges of at least the frontglass substrate.
 31. The vehicular variable reflectance mirrorreflective element of claim 25, wherein the finishing tool comprises agrinding and/or polishing tool that grinds and/or polishes the cut edgesof the front glass substrate and the rear glass substrate during acommon grinding and/or polishing operation.
 32. The vehicular variablereflectance mirror reflective element of claim 25, wherein the backplate is adhesively attached at the rear of the rear glass substrate viadouble-sided tape.